As a method for optically analyzing particles dispersed in a sample liquid (e.g., blood cells in blood and the like), flow cytometry is known. Flow cytometry includes irradiating predetermined irradiation light to particles in a sample liquid advancing through a flow path in a flow cell, obtaining optical characteristics such as light scattering, light absorbance and the like, and performing analysis such as identification, counting and the like of the particles (e.g., patent documents 1, 2).
A particle analysis apparatus used for analyzing particles in a sample liquid based on flow cytometry is called flow cytometer, and the main constitution comprises, as shown in FIG. 6, a flow cell 110, an optical device (in the example of FIG. 6, a light source device OP11, an optical element (lens and the like) OP12 on the irradiation side, an optical element OP13 on the light receiving side, and a light receiving device OP14) and a control device (not shown). In the particle analysis apparatus of FIG. 6, a sample liquid M10 containing particles X10 flows through a flow path 111 in a flow cell 110, the optical device irradiates irradiation light L10 on the flow cell and receives the light L20 obtained by the irradiation, and the control device processes a light-reception signal obtained from the light receiving device and performs analyses of particles size, classification of particles based on the size, particle frequency distribution and the like. In the particle analysis apparatus exemplified in FIG. 6, the flows of sheath liquids M20, M30 surround doubly on the periphery of the sample liquid M10, and by this constitution, particles flow stably one by one in the flow path.
In the particle analysis apparatus exemplified in FIG. 6, electrodes E10, E20 are formed on the upstream side and the downstream side of the flow path so that the particles can also be measured in the flow cell based on the impedance method (electric resistance method). When a particle X10 passes through an aperture (fine pore) 112, the voltage or current between the aforementioned electrodes changes. The impedance method is a method for specifying the particle size based on the values of voltage and current. A particle analysis apparatus for performing a method that simultaneously conducts flow cytometry and impedance method (also called light-focused flow impedance method) is also encompassed in the particle analysis apparatus for analyzing particles in a sample liquid based on flow cytometry. In the following, the particle analysis apparatus in the present specification is an analysis apparatus provided with at least a constitution for analyzing particles in a sample liquid based on flow cytometry.
Patent Document 1 JP-A-H09-257684
Patent Document 2 JP-A-2016-024024
During production, maintenance and the like of a particle analysis apparatus, the center axis of the flow path of the flow cell is aligned with the optical axis of the irradiation light of the optical device (hereinafter to be also referred to as “optical axis adjustment”), and gain adjustment (adjustment of amplification of light-reception signal, light-receiving sensitivity and the like) of light-reception signals is performed.
For optical axis adjustment, a standard solution for flow cytometry containing standard particles is generally used, and displacement of a flow cell (or displacement of an optical device) needs to be adjusted while observing the intensity of the light-reception signal (=intensity of transmitted light), such that the intensity of the light-reception signal, when the irradiation light is irradiated on the standard particles flowing through the flow path, is lowest due to light absorption, scattering, and the like (namely, such that the irradiation light is best blocked by particles). Therefore, during adjustment of the optical axis, an oscilloscope is utilized to check the intensity of the light-reception signal with high real-time property.
However, the oscilloscope only shows the intensity of the light-reception signal, and determination of whether the gain adjustment of the light-reception signal is appropriate requires other method, for example, by measuring standard substances such as control blood and the like and confirming based on the measurement values and the like. Therefore, adjustment of light irradiation in a particle analysis apparatus (optical axis adjustment and gain adjustment) is time-consuming requiring preparation and operation of a plurality of measuring apparatuses.
The problem of the present invention is to solve the above-mentioned problem and provide a new device for adjusting light irradiation in a flow cytometer with reduced time and labor.